package com.boyi.shared.util;

import javax.servlet.http.HttpServletRequest;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Map;


/**
 * 自定义访问对象工具类
 * <p>
 * 获取 HttpServletRequest 的IP地址等信息
 *
 * @author 颜培轩
 */
public class RequestUtil {
    private RequestUtil() {
    }

    /**
     * 获取用户真实IP地址，不使用request.getRemoteAddr();的原因是有可能用户使用了代理软件方式避免真实IP地址,
     * 参考文章： http://developer.51cto.com/art/201111/305181.htm
     * <p>
     * 可是，如果通过了多级反向代理的话，X-Forwarded-For的值并不止一个，而是一串IP值，究竟哪个才是真正的用户端的真实IP呢？
     * 答案是取X-Forwarded-For中第一个非unknown的有效IP字符串。
     * <p>
     * 如：X-Forwarded-For：192.168.1.110, 192.168.1.120, 192.168.1.130,
     * 192.168.1.100
     * <p>
     * 用户真实IP为： 192.168.1.110
     *
     * @param request
     * @return
     */
    public static String getIpAddress(HttpServletRequest request) {
        String ip = request.getHeader("x-forwarded-for");
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("Proxy-Client-IP");
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("WL-Proxy-Client-IP");
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("HTTP_CLIENT_IP");
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("HTTP_X_FORWARDED_FOR");
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getRemoteAddr();
        }
        if (ip.equals("127.0.0.1") || ip.equals("0:0:0:0:0:0:0:1")) {
            //根据网卡获取本机配置的IP地址
            InetAddress inetAddress = null;
            try {
                inetAddress = InetAddress.getLocalHost();
            } catch (UnknownHostException e) {
                e.printStackTrace();
            }
            ip = inetAddress.getHostAddress();
        }
        //对于通过多个代理的情况，第一个IP为客户端真实的IP地址，多个IP按照','分割
        if (null != ip && ip.length() > 15) {
            if (ip.indexOf(",") > 0) {
                ip = ip.substring(0, ip.indexOf(","));
            }
        }
        return ip;
    }

    public static Map<String, Object> getParameters(HttpServletRequest request) {
        Enumeration<String> parameterNames = request.getParameterNames();
        Map<String, Object> map = new HashMap<>(16);
        while (parameterNames.hasMoreElements()) {
            String key = parameterNames.nextElement();
            String value = request.getParameter(key);
            map.put(key, value);
        }
        return map;
    }


}